During the medical treatment of a patient, for example during the treatment of tumors, aneurysms and stenoses, a medical treatment device, for example a needle, is inserted into the body and guided to the diseased point in the body. This is then treated for example by puncture or biopsy. In the case of certain organs, for example the spleen, gallbladder, bowel or spinal cord, the medical treatment device, referred to here generally as an implant, has to be guided very precisely to avoid damaging the organ to be treated or adjacent organs.
The doctor can monitor the guiding of the implant within the body in a parallel manner via imaging systems. One problem here is displaying the location of the medical implant within the body in such a manner for medical personnel that the actual position, in particular the relative position of the implant in relation to the individual organs, can be acquired as intuitively as possible by the personnel providing the treatment.
The imaging method used to display the region to be examined generally involves reconstructing 3D image data records from the measurement data of an angiography, computed tomography (CT) or magnetic resonance (MR) system and reproducing them as required as a three-dimensional image of the region to be examined. The systems listed here therefore supply image volume data relating to the region to be examined. Contrast agents are frequently injected to improve the display.
The current position of the implant is generally superimposed in the images thus reconstructed. To this end the actual position of the implant is acquired for example via location sensors attached to the implant. The location coordinates of the implant thus acquired are then correlated with the coordinates of the image data record, to ensure that the display in the image corresponds to actual circumstances. With such a visualization of the implant in a three-dimensional image, it is however often difficult for the personnel providing the treatment to orient themselves, due to the complexity of the individual organs. It is particularly difficult for medical personal to identify how the implant will progress further.
As an alternative to visualizing the implant in a 3D image, it is also possible to visualize it in a two-dimensional image display, for example what is known as multiplanar reconstruction of the 3D data record. However intuitive acquisition of the relationship between the implant and the tissue being passed through is difficult here too.
Further options for orientation when guiding the implant involve showing up individual vessels using fluoroscopy, e.g. by means of contrast agents, to obtain orientation points or carrying out image reconstruction at short intervals, in particular what is known as 3D angio-reconstruction, to be able to establish the location of the implant in each instance. Finally doctors can simply rely on their anatomical knowledge and insert the implant more or less blindly into the body during fluoroscopic examination of the region to be examined, until it reaches the required point.